In the commonly assigned U.S. Pat. No. 4,528,016 issued 9 July 1985 to Douglas M. CANFIELD, a glass furnace is described and claimed which has a roller conveyor in which conveyor rollers extend across the full width of the furnace chamber and are supported at opposite ends upon stub rollers which thereby cradle the fused silica conveyor rollers. The stub rollers, in turn, are driven by belts which alternately overshoot each stub roller and undershoot an idler roller between each pair of stub rollers along each side of the furnace chamber, the belt being driven by a motor.
In that patent, moreover, the fused rollers rest upon the belt.
In that patent and in commonly owned U.S. Pat. No. 4,601,743, issued 22 July 1986 to Douglas M. CANFIELD and in the reissue patent RE 32 497 of 8 September 1987, scanning thermographic equipment is claimed for controlling the individual heating elements of the furnace to obtain a desired heating profile.
Attention may also be directed to recently issued U.S. Pat. No. 4,725,300 of 16 February 1988 which discloses a cradled-roll conveyer in which alternating stub rollers are driven worm gearing through respective worm-gear transmissions having a common drive shaft.
Notwithstanding the rapid advances made in recent years in such glass-treating furnaces, there are a number of problems which have not been fully resolved heretofore.
For example, the drive energy required to operate the roller conveyor in all of these earlier systems is greater than is desirable.
Problems are encountered in earlier systems with respect to maintaining the fused rollers in position on the stub rollers without subjecting the fused rollers to excessive wear.
Another problem is the delivery of the driving force to the fused roller without unnecessarily constraining the latter under the high temperature conditions to which the fused roller may be subject within the furnace chamber.
By and large, in addition, the earlier furnace systems lack versatility, at least in some respects.